1. Field of the Invention
The invention relates to a method for comparing signals, and more particularly, to a method for identifying interfering transmitters from among a plurality of known satellite transmitters, where methods are utilized in the context of quantum information theory for the comparison of the signals.
2. Description of the Related Art
What is understood by the concept V† of a matrix in the context of the present application is always the adjoint matrix of the matrix V, which is obtained as the conjugate complex matrix of the transposed matrix of V.
Different methods of comparing individual signals with one another are known from the prior art. In particular, individual signals can be transformed via different transformations and the transformation results thus determined can be compared with one another. For certain types of signals, it can be assumed that they each have succeeding signal periods within which the signal has similar signal shapes, though there may also by all means be deviations between the signal shapes. Such signal periods can have arbitrary durations. These signals are represented by different values, such as by sample values that have been recorded at specific sampling time instants.
At present, there is a desire to recognize specific characteristics of substantially periodic signals in an effective manner and if necessary to associate these characteristics with different signal transmitting devices.
The increasing demand for satellite communication links, which has resulted in a high number of different satellite signals, has subsequently led to occurrences of signal interference as a consequence of poor antenna installations. Other reasons for possible signal interference problems may lie in terrorist-related or politically motivated disturbances, but they may also simply be due to the fact that the operators of a station have forgotten to switch off a transmitter. For the operators of satellites, it is therefore necessary not merely to be able to detect signal interference problems, but also to identify their causes and to localize them geographically in order to enable the interfering transmitter to be tracked down without delay.
However, most of the methods known from the prior art have a major disadvantage, i.e., it is necessary to have at least two satellites available when determining the interfering transmitter.